# proto：无法解析无效的 wire-format 数据

- **ID:** `go/proto-unmarshal-cannot-parse-invalid-wire-format`
- **领域:** go
- **类别:** data_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

proto.Unmarshal 收到的字节对于目标消息类型不是有效的 protobuf wire format。典型原因：负载是 JSON/纯文本、被截断、是另一种消息类型，或某个长度分隔字段的 varint 长度前缀已损坏。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| google.golang.org/protobuf 1.28+ | active | — | — |

## 解决方案

1. **** (85% 成功率)
   ```
   Validate and log the raw bytes before unmarshaling, and confirm the wire type matches:

if len(data) == 0 { return errors.New("empty payload") }
if err := proto.Unmarshal(data, msg); err != nil {
    log.Printf("unmarshal failed, first 32 bytes: %x", data[:min(32,len(data))])
    return fmt.Errorf("bad proto payload: %w", err)
}
   ```
2. **** (80% 成功率)
   ```
   Ensure the sender and receiver use the same generated message and that framing (length prefix) is stripped correctly, e.g. with a length-delimited reader:

r := protoio.NewDelimitedReader(conn, 1<<20)
msg := &pb.Foo{}
if err := r.ReadMsg(msg); err != nil { return err }
   ```

## 无效尝试

- **** — Wire-format parsing is deterministic; identical bytes always fail identically. Retrying wastes CPU and never succeeds. (98% 失败率)
- **** — If the bytes are binary protobuf, protojson will reject them; if they are JSON, the original proto.Unmarshal was simply the wrong parser choice — the fix is picking the right one, not blindly swapping. (75% 失败率)